Island



(No Model.)

V. A. THOMAS.

ATTAGHMENT POR ELECTRIC ARG LAMPS.

No. 459,846. Patented sept. 22, 1891'.v

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UNrTED STATES PATENT OFFICE.

VAN A. THOMAS, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR OF ONE-HALF TO ANDREW D. ROSS, OF SAME PLACE.

ATTACHMENT FOR ELECTRIC-ARC LAMPS.

SPECIFICATION forming part of Letters Patent No. 459,846, dated September 22, 1891.

Application filed January 8, 1891.

To all whom t may concern:

Be it known that I, VAN A. THOMAS, a citi- Zen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Non-Conductin g Hoods or Shieldsfor Arc Lamps; and I do hereby declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings,

which form a part of this specification.

My present invention has relation to electric lights, but more especially to the class of arc lights, or rather' to the lower portion of the lamps, adapted to arc lighting; and it consists, essentially, of an insulating hood or shield arranged to be readily attached to and inclose the lower or exposed metallic portion of the lamp.

Heretofore, so far as I am aware, the lower exposed portions extending below the glass globes of arc lampsr-as, for example, the detachable plate or holder carrying one or more lower-carbon electrodes-have been unprovided with suitable non-conducting guards or protectors. It is true that the interior of the carbon-holding tubes is sometimes lined with non-conducting material; but it practically soon becomes worn through by the frequent renewal of the carbons. It occasionally happens that a person carrying an open umbrella receives an electric current from a burning arc lamp by reason of its'contact with some metallic portion of the lower part of the lamp. The danger from this source is obviously greatly increased during rainy weather. I would state, however, that the danger or risk just referred to applies mainly to what are termed commercial lights, as distinguished from street or municipal lights, because as a rule the former are suspended in front of store-windows and but a comparatively few feet from the sidewalks.

In the accompanying sheet of drawings, Figure 1 represents a side elevation of my improved non-conducting shield adapted to be attached to the lower portion of an arc lamp. Fig. 2 is a sectional view taken through the therein by a screw s4.

Serial No. 377,129. (No model.)

center of the glass globe and shield, showing the latter in position asin use, and also showing a portion of the lamp itself. Fig. 3 is a similar view taken on line ma: of Fig. 2. Fig. 4 is an enlarged sectional View showing the manner of holding the shield in place, the heads of the retaining-screws being insulated. Fig. 5 is a side view of the shield having a modified form; and Figs. 6 and are sectional views similar to Figs. 2 and 3, showing the modified shield attached to the lamp as in use.

Again referring to the drawings, B indicates an arc lamp of usual construction provided with a supporting-frame Z).

ce a designate the carbon electrodes mounted substantially as common.

d indicates a bottom plate or holder, hav-4 ing a central downwardly-extendingcentrallybored hub d2, through which the guide-rod o freely passes, the latter being held in position The holder is further provided with tapped ears d', carrying screws s, arranged to hold the glass globe gin place. (See Fig. 4, dro.) The plate d is also furnished with two tubes e, Figs. `2 and 6, arranged to receive and hold the two lower carbons. These tubes are sometimes provided with swinging caps to cover the bottom ends, thereby permitting the carbons to be inserted at that end; but practically the lamp-trimmers prefer to loosen the screw S4 and drop the plate to its limit or stop c4 and introduce the carbons at the top of the tubes e.

The foregoing forms no part of my present invention. Therefore I make no claim to the lamp itself, except as combined with the nonconducting hood about to be described.

A indicates the hood or shield, made, preferably, of non-conductin g material, as rubber, and having a degree of fiexibility, although other substances or compositions may be employed#as, for example, paper or fabric ren- IOO be charged with electricity. The upper portion of the hood forms a circular ange m, arranged to receive the plate d and its ears d. The ange m is provided with a Series of holes 7L, through Which the screws s freely pass to engage the saidv ears. In order to protect the said screws s s, I provide the heads .5" thereof with non-conducting' caps s? of hard rubber', vuleanite, or other suitable material. The shank portions of each of these screws exterior of the shield A, I surround With a short piece of rubber tubing t or other noneonducting materials, thereby completely iusulating the screws, all as clearly shown in Fig. 4. I would state that the hoods A may be permanently attached to the lamp Without departing from the spirit of the invention. In fact, practically, the lamp-trimmer does not usually remove the hoods in making his daily round of duties.

I claim as my invention and desire to secure by United States Letters PatentM l. An insulating or non-conducting;` hood having open ends and fastening devices at one end, by Which it is adapted to be removably secured to the base or lower portion of an arc lamp, substantially as hereinbefore described.

2. The combination, with an are lamp, of a non-con d ueting or insulating hood removably secured thereto and surrounding the lower or exposed metallic portions extending below the glass globe, substantially as described.

3. The combination of an arc lamp provided with non-conducting holding-screws, as s, and a detachably-secured non-conducting` open-ended shield or hood A, surrounding the metallic or conducting portions extending below the glass globe or shade of the lamp, substantially as hereinhefore described, and for the purpose set forth.

In testimony whereoi I have afxed my naturcin presence of two witnesses.

VAN A. THOMAS. Witnesses:

GHARLns HANNIGAN, GEO. H. REMINGTON, 

